During the course of an automobile race, it is often necessary for the participating race cars to make pit stops to change tires. The reasons may be varied, e.g., track conditions, tire wear, wheel problems, or the like. Time spent in the pits is critical to the outcome of a race. In the case of NASCAR races, current rules allow only two impact wrenches fitted with sockets adapted to remove and replace wheel lug nuts to be present over the safety wall of the track. This means little margin for error is present if the tires of a race car are to be changed in a minimum period of time.
The most common problem that slows down the changing of race car tires is that the lug nuts tend to jam in the wrench sockets. One reason for this jamming is that the socket opening is slightly oversized to allow quick engagement of the lug nut with the socket. When jamming occurs, it is often necessary for the pit crew member to stop and insert a screw driver blade into the socket to free the jammed lug nut.
Jam releasing wrench sockets have been suggested by the prior art. They are subject to several deficiencies that render them not suitable for removing jammed lug nuts from wrench sockets which are used to change tires of race cars. The primary approach shown by the prior art to free jammed lug nuts from wrench sockets is to use a retractable plunger that fits inside the socket and by the exertion of a downward thrusting force disengages the jam. These prior art devices, while perhaps working in light duty situations, are not capable of affording a socket which could function with any degree of certainty in the environment of changing the lug nuts of race cars during pit stops.
A plunger fitted wrench socket to be capable of use in the changing of race car tires during pit stops must contain a slightly oversized lug nut engaging opening to allow the socket to quickly engage the lug nuts of race cars. Most importantly, the plunger must engage the socket in a snug, non-slipping, unitary relationship so as to minimize wear on the socket and the plunger. This non-slipping relationship between the two parts, which affords rotational stability, must also be sufficiently strong so as to allow the socket and plunger to withstand the tremendous forces generated by pneumatic impact wrenches. The wrenches used to change racing car wheels have torques of about 500 lbs./sq. in. Also, the plunger must be capable of releasing a jammed lug nut from the socket quickly and without the use of wasted hand or arm motion. Due to design characteristics of earlier described wrenches, they are not capable of meeting these standards. Finally, most earlier described plunger fitted jammed lug nut extracting wrench sockets are incapable of disassembly for maintenance and part replacement. If it were possible to provide a plunger fitted wrench socket capable of meeting the above criteria, an advance in the art would be afforded.